diff --git a/mainwindow.cpp b/mainwindow.cpp
index 99a5739..a41892a 100644
--- a/mainwindow.cpp
+++ b/mainwindow.cpp
@@ -39,7 +39,7 @@ void MainWindow::enumerateDevices()
 	{
 		uint16_t serial = serials[i];
 		std::shared_ptr<struct eismultiplexer> multiplexer(new struct eismultiplexer);
-		if (eismultiplexer_connect(multiplexer.get(), serial) >= 0)
+		if (!eismultiplexer_connect(multiplexer.get(), serial))
 		{
 			uint16_t channelCount = 0;
 			qDebug()<<"Adding channels from device "<<serial;